Brazil's largest grocery chain has pledged to stop selling beef produced on deforested land in the Amazon rainforest in what campaigners say is a victory for the environment and human rights.

Food retailer Pão de Açúcar also promised to stop buying beef produced by workers living in slave-like conditions, or cattle produced on land grabbed from local communities.

The grocery chain has hired consulting firms to audit their supply chains and the firm will cut ties with businesses causing deforestation in the Amazon, said a spokeswomen for Greenpeace Brazil which welcomed the new purchasing plan — to be implemented by the end of June — as a step in the right direction.

"To operate in the Amazon, companies must stop buying from farms involved in land-grabbing, slavery or deforestation," Greenpeace's Adriana Charoux told the Thomson Reuters Foundation. "They have a lot of work to do before June 30."

Representatives of Pão de Açúcar were unavailable for interviews.

"We have worked to mitigate the social and environmental risks of our supply chains," a company spokeswoman said in a statement issued last week.

The firm operates 832 stores across Brazil and has pledged to help its suppliers improve their practices ahead of the June deadline.

Cattle industry

Cattle production is the main driver of Amazon deforestation, Charoux said. About 60 percent the land that was once rainforest is now occupied by cattle.

Once one of the worst offenders for deforestation due to land clearing in the Amazon rainforest, Brazil has seen major improvements in recent years, as the government and companies have tried to address the problem.

The rate of deforestation has fallen by nearly 80 percent since 2003, according to a study published last year.

But with South America's largest country in the midst of a recession, some rural politicians are pushing the government to relax environmental protection in an attempt to boost economic growth.

The cattle industry is one of the main industries employing enslaved workers in Brazil, Charoux said.

Between 1995 and 2015, nearly 50,000 people were freed from slave-like conditions in the country, with most working in the textile sector of the cattle business, she said, citing official figures.

Pão de Açúcar has pledged to be transparent in which businesses it buys beef from, making it easier for monitoring groups to track whether these suppliers are involved in slavery, deforestation or unfair land deals, Charoux said.

"This is a clear signal to all its suppliers, and the market as a whole, that the meat comes from deforestation is no longer accepted by society," Charoux said, crediting Brazilian consumers for pressuring the company to improve its practices.